Electric toothbrushes utilize an electric motor to drive a brush head to provide a brushing action for cleaning teeth. One such toothbrush is disclosed by Sham in U.S. Pat. No. 5,822.821. Sham discloses an electric toothbrush having a motor, which drives a driven gear. The driven gear drives a crank member. The crank member, in turn drives a reciprocating rocker arm. The rocker arm, in turn, drives a brush head. The rate of rotation of the driven gear in the device determines the frequency of reciprocation of the brush head, while the length and shape of the crank member determine the angular sweep and the average angular speed of the brush head.